Dental fluoroscopic instrument



Dec. 1 1938; L c PELKUS El AL DENTAL FLUOROSCOPIC INSTRUMENT Filed Dec. 25, 1934 Fig.1. Fig.2. Fig.3. Fig.4. 1 .5.

Patented Dec. 13, 1938 UNITED STATES PATENT OFFICE Leo C. Pelkus and Henry L. Pelkus, Jr., Boston, Mass.

Application December 25, 1934, Serial No. 759,133

6 Claims.

This invention relates to fluoroscopy and more particularly to instrumentalities for dental fluoroscopic examination.

In the specification and claims, the term cassette is intended to refer to the combination of fluorescent screen and holder or container for said screen.

An object of this invention is to provide an improved instrument for dental fluoroscopy, and one which is sterilizable in its assembled condition.

Another object is to provide an improved dental fluoroscopic cassette, and one in which the fluorescent material is protected from body fluids and sterilizing materials.

-A further object is to provide an improved fluorescent screen which may be used in a dental fluoroscopic cassette.

Another object is to provide an attachment which may be readily and detachably secured to a dental mirorr to form therewith a dental fluoroscope.

Other objects will be apparent to those skilled in the art to which this invention appertains from the disclosures made in the specification and claims and accompanying drawings.

In the accomplishment of the above and other objects we have provided fluoroscopic instrumentalities which may be employed where the image on the fluorescent screen is viewed directly, or indirectly by reflection, and which may be sterilized without disassembly thereof or removal of the fluorescent screen. Thus a cassette of this invention may comprise fluorescent material enclosed between two layers of materials impervious to moisture but pervious to X-rays, the unit being sealed at its edges against the entrance of moisture at that point.

In one form of the invention, a dental instrument which may be used for either direct or indirect vision of the image includes a handle, a mirror carried by the handle, and a fluoroscopic cassette or fluorescent screen holder adjustably associated with and secured to said mirror. The cassette may be adjustable angularly with relation to the mirror and preferably may also be adjusted circumferentially with respect thereto. While the entire instrument may be manufactured as a unit, a preferred form of the invention contemplates the manufacture of the eassette and associated parts as an attachment which may be removably secured to a dental mirror of the usual type. The cassette itself, moreover, involves certain advantageous features of construction and is liquid-tight, so that when the instrument is placed in the mouth the saliva cannot reach the fluorescent material, and, furthermore, the cassette may be readily sterilized without requiring disassembly thereof or removal of the fluorescent screen. We have further 5 provided an improved fluorescent screen the base of which is itself not only X-ray permeable, but liquid impermeable, thus permitting a simplification of the cassette construction as well as a less obstructed path for the X-rays, with conse- 10 quent brighter images.

In the accompanying drawing, which illustrates certain specific embodiments of the invention,

Figures 1 and 2 are fragmentary perspective views, partly in section, of novel and improved fluorescent screens;

Figs. 3, 4, 5 and 6 are fragmentary perspective views, partly in section, of fluoroscopic cassettes in accordance with this invention;

Fig. '7 is a perspective view, partly broken away, 20 of a dental fluoroscopic instrument suitable for use where the image on the fluorescent screen may be viewed directly;

Fig. 8 is a perspective view of a dental fluoroscopic attachment according to this invention, shown in association with a dental mirror to constitute therewith an instrument which may be used for indirect, and also direct, vision of the image;

Fig. 9 is another perspective view of the attachment shown in Fig. 8 and showing in greater detail the arcuate means for associating the attachment with the dental mirror;

Fig. 10 is another perspective view of the fluoroscopic attachment illustrated in Figs. 8 and 9 and showing the arcuate clip folded over adjacent to the cassette and with a protective member in the clip to protect the cassette when not in use;

Fig. 11 is a perspective view of a modified form of attachment wherein the cassette is also removable, the attachment being shown in operative association with a dental mirror;

Fig. 12 is a plan View of the lower portion of the mouth, and illustrating the use of an instru- 45 ment such as shown in Fig. '7 where direct vision of the image may be had; and

Fig. 13 is a fragmentary vertical section of the mouth, and showing in elevation an instrument like that of Fig. 8 in position for fluoroscopic examination where the image on the fluorescent screen is viewed indirectly by means of the mirror.

In Fig. 1 we have ilustrated a novel form of fluorescent screen wherein the fluorescent mate- 5 rial I is adhesively secured directly to a base 2 which is not only X-ray permeable, but also heat-resistant and resistant or impermeable to liquids with which the base of the screen may come in contact during medical or dental use, for example, saliva and blood, as well as cold or hot water, steam, alcohol, and other cleaning and sterilizing media. The term liquid impermeable will be used in the specification and claims to denote materials impermeable to the above and similar materials. While the base 2, as illustrated, is of Bakelite, it may consist of other synthetic resins, cellulose derivative plastics, aluminum, or other X-ray permeable metal, glass, or any other suitable material of the requisite characteristics. The thickness of the base 2 may be varied within relatively wide limits depending upon the particular use in View and upon the particular material employed. For use in dental fiucroscopy, however, we have found that a base made of Bakelite of ,6 inch thickness is very suitable. The base 2, which may form an exterior surface of the fluoroscopic instrument, is preferably made as thin as possible in order to offer the least obstruction to the passage of X- rays therethrough, and thus to provide an image on the fluorescent screen of maximum clarity. The upper surface of the base 2, to which the coating of fluorescent material I is adhesively secured, is preferably roughened in order to provide improved adhesion of the fluorescent material to the base.

The fluorescent material I may be of any suitable nature, but for greatest clarity of image we prefer the use of comminuted fluorescent material such as employed in Patterson Type B Fluoroscopic Screens, manufactured by The Patterson Screen Co. of Towanda, Pa., U. S. A. We are not aware of the exact nature of the fluorescent chemicals employed in such Patterson Type B screens but they may include one or more of the following materials: activated zinc silicate, potassium uranyl sulfate, calcium tungstate, and cadmium tungstate.

In Fig. 2 auniform layer of fluorescent material I is shown as adhesively secured to a transparent glass base material 3. In use, a screen such as shown in Fig. 2 is preferably so disposed that the operator looks through the transparent glass base 3 to View the image formed on the fluorescent material I.

In Figs. 3 to 7, inclusive, we have shown various forms of cassette in accordance with this invention. In Fig. 3 there is shown a cup-shaped transparent glass cover member 4, a liquid impermeable base member 2, such as of Bakelite, and fluorescent material I intermediate the base 2 and the face 5 of the glass member 4. Alternatively, of course, the base 2 might be of' glass or other material. The fluorescent material is shown as attached to the base member 2, similar to the construction shown in Fig. 1, although the fluorescent material may alternatively be adhesively attached to the glass 4. Means such as liquid impermeable filler or cement 6 is preferably dispcsed between the contiguous side walls of the members 2 and 4 in order to prevent access of liquid to the interior of the cassette during use or during sterilization. Such filler 6 may be composed of rubber, shellac, varnish, pyroxylin, or other suitable materials.

In Fig. i is. shown a modified form of cassette 8 wherein fluorescent material I is adhesively secured to a cardboard 9 as in the usual construction of Patterson Type B fluorescent screens, the

material I and cardboard 9 being entirely surrounded by a unitary covering IE2 of any suitable material. The face II of the covering Iil adjacent to the fluorescent material I is preferably transparent. The covering It may be of a cellulose derivative, such as pyroxylin, and may be formed by molding, or in any other suitable manner, as by dipping the fluorescent screen in a cellulose derivative solution, such as collodion, and permitting the solvent to evaporate to deposit the unitary, liquid impermeable coating Ill.

In Fig. 5 is shown a form of cassette wherein the fluorescent material l is disposed between a liquid impermeable base 2, such as of Bakelite, and a transparent cover member 3, such as of glass. The fluorescent material I may be adhesively secured to the base 2 in the manner shown in Fig. l, or to the glass 3 in the manner shown in Fig. 2. Around the periphery of the base 2 and glass 3 is shown a continuous ring-shaped or annular frame member id of U-shaped crosssection. The ring it may be formed of a moldable plastic, such as Bakelite, or may be of metal. Liquid impermeable cement or filler ii is shown disposed intermediate the inner surfaces of the ring I4 and the adjacent portions of the members I, 2 and 3 in order to prevent access of liquid to the interior of the cassette. The filler ii may of course be omitted where the mechanical union of the parts is such as to render the filler unnecessary.

In Fig. 6 is shown a cassette I6 whose outer surface is formed by a glass cover I8 and a liquid impermeable, X-ray permeable shell 28. Within the shell 2t, and retained by the shoulder portion 22, is shown a fluorescent screen comprising a cardboard or other base 5 and fluorescent material I. Cement or filler 5 is disposedbetween inner surfaces of the shell 2:? and the members I and I8 in order to render the cassette liquid-tight. The shell 29 may be of molded plastic material, X-ray permeable metal, or other suitable material.

Another form of cassette 2%, is shown in Fig. 7,

wherein the fluorescent material I is adhesively secured to a Bakelite base 2 to form a fluorescent screen. A glass or other transparent plate 26 is disposed adjacent to the fluorescent material I. A rubber gasket 27 tightly engages the associated peripheral surfaces of the screen and plate 26, holds said screen and plate in associated relation, and extends inwardly over the outer radial surfaces of the associated parts. The metal, cylindrical, interiorly-threaded frame 28 has a shouldered portion 30 adjacent to one end thereof. The associated plate 26 and screen are disposed within the frame 28 with the gasket 27 intermediate said associated screen and plate on the one hand, and the threaded and shouldered portions of the frame 28 on the other hand. A metal washer or ring 32 is disposed within the frame in contact with the other radially extending portion of the gasket 27. An exteriorly-threaded ring 33 cooperates with the interior threads of the frame 28 and serves to maintain the cassette parts in tightly associated relation, wherein access of liquid to the fluorescent material I is prevented. If desired, additional filler material or adhesive 6 may be disposed between the exterior portions of the gasket 2? and the adjacent portions of the frame 28 and washer 32. A handle 34 of a type common in dental mirrors and other instruments is shown secured to the cassette by means of a bifurcated portion 35. The cassette 2t and the handle 34 constitute an instrument which may be employed where direct vision of the image on the fluorescent material may be had, though it will be understood that for this purpose any of the cassettes shown in Figs. 3 to 6, inclusive, may be associated with suitable handles.

In Figs. 8, 9 and 10 we have illustrated an attachment comprising a cassette 38, an attaching member 40 arranged to engage a dental mirror 44 at the marginal portion thereof and Without substantially obstructing the reflecting surface thereof, and adjustable connecting means 42 uniting the cassette and attaching means and permitting angular adjustment therebetween. The mirror may have a plane reflecting surface, or a concave reflecting surface where a magniflcation of the image is desired. The cassette may be of any of the modifications described above in reference to Figs. 3 to 7, inclusive, but as illustrated is of the form shown in Fig. 7. The mirror attachment member or clip 40 is of arcuate shape, preferably somewhat resilient, and is arranged to grip the marginal portion of the mirror 44 over slightly more than half the periphery thereof, and is adjustable circumferentially of the mirror. The mirror 44 is provided with a handle 46. The interior surface of the member 40 is shaped to conform generally to the exterior marginal contour of the mirror. While the connecting means 42 is preferably adjustable and may be of any suitable and convenient form, it is illustrated as comprising a slotted member 48 integrally united to the cassette 38, and a tongue member 50 integrally united to the arcuate member 40. The tongue member 50 is disposed in the slot 52 in the member 48 and is held by a screw 54 in such manner that the cassette 38 may be angularly adjusted with respect to the arcuate member 40 and mirror 44 and will remain in any position of angular adjustment.

When the fluoroscope is not in use, and in order to prevent undue exposure of the fluorescent screen to the light, the cassette may be folded over against the dental mirror, or the attachment may be removed from the mirror, and, as illustrated in Fig. 10, the arcuate member 40 folded over adjacent to the cassette 38, and a light impermeable plate 60, such as of Bakelite, disposed within the member 40.

In Fig. 11 is shown a modification wherein the adjustable connecting means 42 is disposed between and secured to two arcuate resilient attaching members or clips 40 and 62. The member 40 is arranged to be secured to a dental mirror of conventional type, and having a plane or concave reflecting surface. In Fig. 11 a cassette 24 of the construction shown in Fig. '7 is disposed within the arcuate member 62, although it is contemplated that the member 62 may be arranged to receive a cassette of any of the types shown in Figs. 3 to 7, inclusive. The construction shown in Fig. 11 is advantageous where the removability or replaceability of the cassette 24 is desirable.

Figs. 12 and 13 illustrate the mode of employing instruments of this invention in the fluoroscopic examination of teeth. The cone 64 of the X-ray machine is placed opposite the particular tooth or teeth to be examined. The cassette is thus held in such a position that the image of the desired tooth will appear on the fluorescent screen. In Fig. 12 is illustrated a case where the image on the fluorescent screen may be viewed directly. The dotted line 66 indicates a line of vision. The instrument shown is similar to that of Fig. '7. v I f In Fig". '13 is illustrated a case wherein the image is examined indirectly, by reflection in a mirror. The instrument, of the type shown in Fig. 8, is held in such a position that the image ma be vie ed. the mirror 44; The dotted lines 68 andid indicat'e'lines of vision. It will be observed that in ordinary use the cassette 38 overlies the mirror 44 and is disposed at an acute angle therewith.

It should be understood that instruments of the type shown in Figs. 8, 11 and 12 may also be used in cases where the image may be viewed directly on the fluorescent screen. This is accomplished by increasing the angle between the cassette and mirror, if necessary, and holding the cassette in the requisite position for direct vision of the fluorescent screen thereof.

While the cassettes described above are shown as substantially circular in shape, it will be understood that the cassettes may be of polygonal, curvilinear, or any other suitable shape.

It will be seen that our invention makes possible the rapid and economical survey of the teeth to determine the presence of hidden tooth defects, such as ulcers, internal cavities, impactions, tooth fragments after extraction, etc. Where X-ray photography is indicated, our invention makes possible a preliminary examination so as to eliminate unnecessary photographs, and to determine the most suitable angle or position from which to make the desired photographs. By reason of the ease, rapidity and economy afforded for frequent fluoroscopic surveys of tooth conditions, our invention makes possible the early detection and remedy of unsound tooth conditions, with the obvious advantages flowing therefrom, including the saving of many tooth structures, defects in which might otherwise remain undetected until too late to prevent the necessity for extraction.

Our invention, furthermore, has very distinct advantages in following the course of certain operations. Thus, for example, the filling of root canals, which has hitherto been attended either by guesswork as to the depth location of the filling, or by the slow method of X-ray photography, may now be carried out rapidly and accurately by fluoroscopic observations of the progress of the operation.

It should further be noted that our invention makes dental fluoroscopy practicable for general professional practice by reason of constructional features permitting ready sterilization of the fluoroscopic instrument. Moreover, we have provided simple and readily employed instrumentalities which may be used for either direct or indirect vision of the fluoroscopic image, and one form of which may be associated with a conventional dental mirror. By other features of construction of the fluorescent screen and cassette, we have provided a cassette of advantageous characteristics and one offering a minimum resistance to the passage of X-rays. It should be noted, however, that certain features of the invention, including fluorescent screen and cassette, are not limited to use in dental fluoroscopy. Furthermore, it is to be understood that various changes and modifications may be made in the instrumentalities described herein without departing from our invention.

Having described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

pair of moisture-impervious but X-ray pervious plates carried on said shoulder and with a layer of fluorescent material therebetween, one of said plates being transparent, a gasket holding said plates in assembled relation and engaging same at the peripheral and marginal portions thereof, a washer member at the end thereof opposed to said shoulder and adjacent to one of said plates, and an externally threaded ring member threaded into said frame to hold the cassette members in assembled relation and to prevent access of liquid to said fluorescent material.

2. In a fluoroscopic attachment for dental mirrors, in combination, a cassette, and means forsecuring said cassette to a dental mirror, said cassette comprising a synthetic resin base, fluorescent material secured directly to said base, a glass plate superposed on said base and contiguous to said fluorescent material, and an annular frame holding said base and plate in assembled relation and arranged to prevent access of liquid to said fluorescent material.

3. In combination, a cassette comprising fluorescent material enclosed between two layers of materials impervious to moisture but pervious to X-rays, the unit being sealed at its edges against the entrance of moisture at that point.

7 4. In combination, a cassette comprising fluorescent material enclosed between two layers of materials impervious to moisture but pervious to X-rays, one of said layers being of a transparent nature such as glass, the unit being sealed at its edges against the entrance of moisture at that point. v

5. In combination, a cassette comprising fluorescent material enclosed between two layers of materials impervious to moisture but pervious to X-rays, the unit being sealed at its edges against the entrance of moisture at that point by means of a gasketand a frame.

6. In a fluoroscopic attachment for dental mirrors, in combination, a cassette comp-rising fluorescent material enclosed between two layers of materials impervious to moisture but pervious. to X-rays, the unit being sealed at its edges against the entrance of moisture at that point by means including a metal frame, and'an arcuate clip arranged to engage the peripheral portion of a dental mirror, said clip being secured in hinged relation to the metal frame of the cassette.

LEO C. PELKUS. HENRY L. PELKUS, JR. 

